Prevent testProviderRefresh test failures due to log ordering differences

Accept either the typical ordering of log messages or an alternate
ordering of log messages in testProviderRefresh.  The same messages are
used in each case, but the sequence of messages changes.

Accepting either ordering assures that we won't have plugin BOM failures
due to timing differences or other differences in test infrastructure.

jenkinsci/bom#5718 (comment)
detected a failure in this test when run within the plugin bill of
materials.

jenkinsci/bom#5720 (comment) tested
more deeply and found that it failed more than 5% of my test runs locally.

Additional local testing confirmed that the order of the log messages was
sometimes slightly different than the original assertion expected. This
change accepts either ordering.

Testing done:

* Before this change, the test would fail 5% of the time on my
  AMD Ryzen 5 5600X 6-Core Processor on Red Hat Enterprise Linux 8
  when run with
  `mvn -Dtest=GithubAppCredentialsTest#testProviderRefresh test`

* After this change, the test passes 100% of the time in the 36 test
  runs that I used to check it

Author: MarkEWaite

src/test/java/org/jenkinsci/plugins/github_branch_source/GithubAppCredentialsTest.java

@@ -287,27 +287,58 @@ public void testProviderRefresh() throws Exception {
 
             List<String> credentialsLog = getOutputLines();
 
+            // Assert that individual messages occur at least once in the credentials log
+            String generatingMsg = "Generating App Installation Token for app ID 54321";
+            String failedMsg =
+                    "Failed to generate new GitHub App Installation Token for app ID 54321: cached token is stale but has not expired";
+
+            // Be sure the expected messages are in the log
+            assertThat(credentialsLog, hasItem(generatingMsg));
+            assertThat(credentialsLog, hasItem(failedMsg));
+
             // Verify correct messages from GitHubAppCredential logger indicating token was retrieved on
             // agent
-            assertThat(
-                    "Creds should cache on master",
-                    credentialsLog,
-                    contains(
-                            // refresh on controller
-                            "Generating App Installation Token for app ID 54321",
-                            // next call uses cached token
-                            // sleep and then refresh stale token
-                            "Generating App Installation Token for app ID 54321",
-                            // next call (error forced by wiremock)
-                            "Failed to generate new GitHub App Installation Token for app ID 54321: cached token is stale but has not expired",
-                            // next call refreshes the still stale token
-                            "Generating App Installation Token for app ID 54321",
-                            // sleep and then refresh stale token hits another error forced by wiremock
-                            "Failed to generate new GitHub App Installation Token for app ID 54321: cached token is stale but has not expired",
-                            // next call refreshes the still stale token
-                            "Generating App Installation Token for app ID 54321"
-                            // next call uses cached token
-                            ));
+            if (credentialsLog.get(2).equals(failedMsg)) {
+                assertThat(
+                        "Creds should cache on master - typical order",
+                        credentialsLog,
+                        contains(
+                                // refresh on controller
+                                generatingMsg,
+                                // next call uses cached token
+                                // sleep and then refresh stale token
+                                generatingMsg,
+                                // next call (error forced by wiremock)
+                                failedMsg,
+                                // next call refreshes the still stale token
+                                generatingMsg,
+                                // sleep and then refresh stale token hits another error forced by wiremock
+                                failedMsg,
+                                // next call refreshes the still stale token
+                                generatingMsg
+                                // next call uses cached token
+                                ));
+            } else {
+                assertThat(
+                        "Creds should cache on master - alternate order",
+                        credentialsLog,
+                        contains(
+                                // refresh on controller
+                                generatingMsg,
+                                // next call uses cached token
+                                // sleep and then refresh stale token
+                                generatingMsg,
+                                // next call refreshes the still stale token
+                                generatingMsg,
+                                // next call (error forced by wiremock)
+                                failedMsg,
+                                // sleep and then refresh stale token hits another error forced by wiremock
+                                failedMsg,
+                                // next call refreshes the still stale token
+                                generatingMsg
+                                // next call uses cached token
+                                ));
+            }
 
             // Getting the token for via AuthorizationProvider on controller should not check rate_limit
             githubApi.verify(